1. Field of the Invention
The present invention relates to a technology of playback control in audio playback devices such as a DVD-Audio playback device that plays back a DVD-Audio disk.
2. Description of the Related Art
According to the DVD-Audio standards, a DVD-Audio playback device is permitted to function as a video-capable audio player (VCAP), which plays back and displays visual data such as video, still pictures and visual menus in addition to a playback audio data, and also function as an audio only player (AOP) that plays back only audio data but does not display the above-described visual data. Then, a DVD-Audio disk can contain an audio title (ATT) playable only on VCAP in addition to an ATT playable on both AOP and VCAP as contents.
Meanwhile, the DVD-Audio playback device that can function as a VCAP is generally capable of functioning also as an AOP in response to a user's selection or the like in many cases. Now, as the audio playback device capable of functioning both as the VCAP and the AOP, there is known a DVD-Audio playback device that functions as the VCAP when it can use a display device and functions as the AOP when it cannot use the display device (Japanese Patent Laid-Open No. 2004-22023 publication, for example).
Incidentally, some users sometimes let the DVD-Audio playback device function as the AOP even in the state where the DVD-Audio playback device can use the display device. This is because simpler operation of the device is possible when it is allowed to function as the AOP rather than the VCAP where the device can provide various operability using visual menus but user's operability often becomes complicated. Further, when the DVD-Audio playback device is applied as an on-vehicle audio device, there are cases where the DVD-Audio playback device is forcibly allowed to function as the AOP even when the DVD-Audio playback device can use a display device in order to prevent a driver from distraction when he/she drives a car.
However, when the DVD-Audio playback device is allowed to function as the AOP as described, there are cases where the user cannot play an ATT contain in the DVD-Audio disk, which is playable only on the VCAP, but also ends the use of the DVD-Audio disk without noticing the presence of the ATT. Then, in this case, a user's opportunity of watching the ATT playable only on the VCAP is lost as a result.